Air guide housings are provided, for example, to guide fresh and recirculated air to the passenger compartment of a vehicle. DE 197 33 052 A1 discloses one such air guide, which has a relatively costly and demanding mounting and guiding of the rotatable air vent body. The bell-like air vent body sits on the lower edge of the fan housing. The intake housing, which has the same bell shape but has two openings (one for fresh air and one for circulating air) is situated around the air vent body. The air leaves the intake housing downward, almost through the bottom of the bell, in order to be drawn in by the fan. When both housing openings are closed, no air is fed to the fan and the air is not circulated in the passenger compartment. In some conditions (e.g., in winter), fogging of the windshield and resulting dangerously poor driver visibility can occur. Also, a comfortable, persistent temperature in the passenger compartment cannot be guaranteed due to no air is passed through the heater or air conditioner. Overall, this is a relatively costly design which can be unreliable in everyday operation.
Another air guide housing, with a pivoting vent or semi-cylindrical drum vent, is described in DE 199 15 966 A1. This structure may be used to supply fresh air and/or circulating air to a fan by means of ribs integrated in the housing, which ribs are supposed to divert the air stream at the entry to the fan and prevent mixing of circulating air and fresh air in front of the fan. However, during slow rotation of the pivot vent or drum vent between the selected positions of fresh air to circulating air, fresh air may flow around the rib directly into the passenger compartment through the circulation inlet. This can be in different conditions be undesirable, particularly in winter.
The present invention is directed toward overcoming one or more of the problems set forth above.